Timing recovery and tracking method and apparatus for data signals

1. A method of timing recovery and tracking with respect to data signal in a digital communication system, said method comprising the steps of: setting a time window for making a decision based upon a predetermined threshold level, said time window having a time period corresponding to a transmission data rate in the digital communication system; detecting a time duration positioned within said time window, a level of a received signal being higher than the predetermined threshold level during said time duration; assuming a substantially middle point of said time duration as an optimum decision point of the received signal; and updating the time window so that the updated time window has its center at a position of said assumed optimum decision point, thereby recovering timing synchronization with the received signal.

2. A method of timing recovery and tracking with respect to data signal in a digital communication system, said method comprising the steps of: setting a time window for making a decision based upon a predetermined threshold level, said time window having a time period corresponding to a transmission data rate in the digital communication system; sampling received signal with a sampling rate which is an integral multiple of the transmission data rate to provide sampled signals; detecting a sampling duration t.sub.i,1 -t.sub.i,n positioned within said time window, levels of the sampled signals being higher than the predetermined threshold level during said sampling duration; assuming a substantially middle point of said sampling duration as an optimum decision point of the received signal; and updating the time window so that the updated time window has its center at a position of said assumed optimum decision point, thereby recovering timing synchronization with the received signal wherein I is a sample and n the number of samples.

3. The method as claimed in claim 2, wherein said assuming step includes a step of assuming m-th sampling point or (m+1)-th sampling point in said sampling duration t.sub.i,1 -t.sub.i,n as said optimum decision point of the received signal when the number n of samples in the sampling duration t.sub.i,1 -t.sub.i,n is an even number (n=2m, m is a natural number).

4. The method as claimed in claim 3, wherein said assuming step includes a step of assuming (m+1)-th sampling point in said sampling duration t.sub.i,1 -t.sub.i,n as an optimum decision point of the received signal when the number n of samples in the sampling duration t.sub.i,1 -t.sub.i,n is an odd number (n=2m+1).

5. An apparatus for timing recovery and tracking with respect to data signal in a digital communication system, said apparatus comprising: means for setting a time window for making a decision based upon a predetermined threshold level, said time window having a time period corresponding to a transmission data rate in the digital communication system; means for detecting a time duration positioned within said time window, a level of a received signal being higher than the predetermined threshold level during said time duration; means for assuming a substantially middle point of said sampling duration as an optimum decision point of the received signal; and means for updating the time window so that the updated time window has its center at a position of said assumed optimum decision point, thereby recovering timing synchronization with the received signal.

6. An apparatus for timing recovery and tracking with respect to data signal in a digital communication system, said apparatus comprising: means for setting a time window for making a decision based upon a predetermined threshold level, said time window having a time period corresponding to a transmission data rate in the digital communication system; means for sampling received signal with a sampling rate which is an integral multiple of the transmission data rate to provide sampled signals; means for detecting a sampling duration t.sub.i,1 -t.sub.i,n positioned within said time window, levels of the sampled signals being higher than the predetermined threshold level during said sampling duration; means for assuming a substantially middle point of said sampling duration as an optimum decision point of the received signal; and means for updating the time window so that the updated time window has its center at a position of said assumed optimum decision point, thereby recovering timing synchronization with the received signal wherein I is a sample number and n the number of samples.

7. The apparatus as claimed in claim 6, wherein said assuming means includes means for assuming m-th sampling point or (m+1)-th sampling point in said sampling duration t.sub.i,1 -t.sub.i,n as said optimum decision point of the received signal when the number n of samples in the sampling duration t.sub.i,1 -t.sub.i,n is an even number (n=2m, m is a natural number).

8. The apparatus as claimed in claim 7, wherein said assuming means includes means for assuming (m+1)-th sampling point in said sampling duration t.sub.i,1 -t.sub.i,n as said optimum decision point of the received signal when the number n of samples in the sampling duration t.sub.i,1 -t.sub.i,n is an odd number (n=2m+1).